Addition of Fe to Ni- and Co-based (oxy)hydroxides has been shown to enhance the activity of these materials for electrochemical oxygen evolution. Here we show that Fe cations bound to the surface of oxidized Au exhibit enhanced oxygen evolution reaction (OER) activity. We find that the OER activity increases with increasing surface concentration of Fe. Density functional theory analysis of the OER energetics reveals that oxygen evolution over Fe cations bound to a hydroxyl-terminated oxidized Au (Fe-Au 2O 3) occurs at an overpotential ~0.3V lower than over hydroxylated Au 2O 3 (0.82V). This finding agrees well with experimental observations andmore » is a consequence of the more optimal binding energetics of OER reaction intermediates at Fe cations bound to the surface of Au 2O 3. These findings suggest that the enhanced OER activity reported recently upon low-potential cycling of Au may be due to surface Fe impurities rather than to "superactive" Au(III) surfaquo species.« less

Reduction in an H{sub 2} flow at 600 C of Fe/MFI prepared by chemical vapor deposition, followed by its exposure to N{sub 2}O at 250 C, produces a highly active state characterized by an unusual TPR spike at 200 C. In situ X-ray absorption near-edge structure, X-ray absorption fine structure data and literature data on DFT calculations suggest that in this state some Fe will be present in the oxidation state of Fe{sup 4+}.

The electrocatalytic site FeN{sub 4}, which is active towards the oxygen reduction reaction, is incorporated into the graphene layer of aligned carbon nanotubes prepared through a chemical vapor deposition process, as is confirmed by X-ray absorption spectroscopy and other characterization techniques.